Parachutes

We decided to try our hand at making parachutes. Once again our brave gingerbread men rose to the occasion. Our first attempt used a coffee filter (nicely hyperbolic), and resulted in a slightly slowed descent. Jr scientist A came up with his own design (on the right), which worked better than mine (what does it say when a 4 year old can design a better parachute than you!). Jr scientist A wanted us to make parachutes for him and his sister, but I think such an endeavor might be a little premature.

Stalagmites and stalactites, take 3

Never willing to admit defeat, we've made another try at making stalagmites and stalactites. We noticed that the area around our crystal experiments was covered with crystals. It seems that the salt water evaporated in the hot sun, but was too heavy to stay in the air and condensed out. We decided to take advantage of this to try to grow stalactites. We put a mesh (a cut-out from a screen door) on top of the jar for our latest experiment, hoping it would catch the escaping evaporated salt water. We poured our crystal making materials into the jar while it was covered by the screen so some of the liquid would stay on the screen and start a layer of crystals for the rest to hang on to. We weren't able to grow stalactites with this technique, but we got an unexpected but happy result. The evaporated salt water seemed to get trapped inside the jar so we ended up with one big thick crystal that covered the bottom of the jar. Pretty cool. I want to try this in a disposable cup next time so we can easily get the crystal out to play with. It looks like we'll finally have crystals that aren't to delicate to handle.

Good clean fun

Today we did an experiment that Jr. scientist A named the messy messy experiment. We made some bubble mix (water + dish detergent)and headed outside to play with bubbles. We used a funnel to make different sized bubbles (depending which end we blew into) and tried out a new bubble maker -two straws connected with string- with mixed results. The experiment ended with playing around in puddles of bubble mix and lots of fun.

Rubber band-powered boat

We used a rubber band-powered boat to investigate potential and kinetic energy. The boat used popsicle sticks held together with hot glue for the body and tape-covered cardboard for the paddle. A rubber band attached to the boat body goes around the paddle. The boat is supposed to go by turning the paddle, storing energy in the rubber band, which is released when you let go of the paddle. Its maiden voyage went well, paddling slowly in the bathtub. Unfortunately, before we could try a stronger rubber band that might store more energy, the boat fell apart. I guess hot glue is not as waterproof as I thought. We'll have to try to make some other rubber band-powered toys.

Water race

To try to show that, even though water looks the same after you dissolve salt in it, it's changed, we decided to compare the speed of diffusion for salt water and fresh water. We filled one bottle with fresh water, dyed green, and a second bottle with water with Epsom salt dissolved into it, dyed red. Then we rolled up a paper towel and put an end in each bottle. The green fresh water started climbing the paper towel. At first it looked like the red salt water was just sitting there, but we checked and the un-dyed paper towel coming from the red was wet, while the paper towel from the fresh water was only wet where it was green. Eventually the red color started moving along the towel. It looks like the salt slowed the diffusion of the color, but not the diffusion of all the water.

Making water run upstream

We decided to try to make water run upstream, so to speak, using diffusion. We filled a bottle with colored water. Then we took a long piece of paper towel, rolled it up, and used string to keep it rolled up. We put one end of the paper towel in the water-filled bottle and the other end in an empty bottle that we put on a raised platform. Nearly instantly the colored water started creeping up the paper towel. We quickly learned that a paper towel saturated with water is much heavier than a dry paper towel and we had to add supports to hold the paper towel up. Throughout the evening we watched its slow progress. We checked on it in the morning and, to our surprise, the water hadn't made it all the way to the other bottle. Instead, it stopped part-way up, leaving a dark ring of color, followed by dry paper towel. I guess diffusion will only go so far.

Stalagmites and stalactites, take 2

Our second attempt at making stalagmites and stalactites with salt crystals. This time we used a paper towel to connect the two jars filled with Epsom salt dissolved in water. The liquid did slowly travel up and across the paper towel, making the paper towel rigid, and we got some crystals forming below the paper towel, but nothing that looked like stalagmites or stalactites. We'll have to keep trying.

Cold air balloon

We tried to inflate a balloon using cold air by sticking a balloon over the opening of an empty bottle we took out of the freezer. The idea was that as the air warms up, it expands, inflating the balloon. We left the bottle and balloon out overnight to warm up the captured air and found a somewhat inflated balloon in the morning. Not a very impressive effect. Maybe we need a bigger bottle.

Stalagmites and stalactites

After visiting a cave exhibit at the zoo, we decided to try to make our own stalagmites and stalactites. We dissolved as much Epsom salt as we could into hot water and divided it into 4 empty baby food jars. We added different food color to each jar and then hung strings between them - some wool and some cotton. Each string was weighted down on either end with a paperclip. The idea was that the water/salt mixture would go along the strings and drop down near the middle where the strings dipped a little. Over time, this should cause some crystals to grow down from the string where the water was dripping from and grow up from the container where the water dripped to. Unfortunately, the liquid never made it up any of the strings, so we never got any stalagmites and stalactites. However, crystals started growing both around the rim of the jars and on the outside sides, and even around the outside base of the jars! We didn't expect that - and it saved our experiment from complete disaster.

Growing crystals

We tried to make crystals by dissolving Epsom salt in water. We heated water up in the microwave (so we could dissolve the salt at the table in plain view). After we dissolved as much salt as we could (with some undissolved salt sitting at the bottom of the cup) we microwaved it again. This dissolved the remaining salt and let us mix more in. We repeated this a couple times, added food coloring, and poured a shallow layer of the solution into a tupperware container. After letting it sit a couple days so the water could evaporate, we were left with some rather unimpressive crystals. It was essentially a somewhat sparkly layer of material. We'll have to work on making better looking crystals.